Larger midterm victory: 1958 for the Democrats or 1994 for the Republicans

[progressive85]

I say 1994.  1958's gains were reversed in 1960 where Democrats lost a lot of seats in the House despite barely (and that's controversial itself) winning the Presidency.  It was a short-time bounce.  Only after Kennedy's assassination in '63 and LBJ's landslide in '64 did the Democrats have enough votes to really pass the huge Great Society agenda, which included many landmark laws.  I will say that the Senate 1958 results gave Democrats an edge for years in keeping the Senate since they did very VERY well in those Senate races, but if you look at the 6 years before that (1952) that was a Republican year and the 6 before that (1946) that was a really Republican year, so there were vulnerable R incumbents that would not survive a Democratic wave.

1994 had this Earth-shattering (at the time) quality to it because for 40 whole years the Republicans were the minority in the House (and even in the Senate, only had it for the first 6 years under Reagan), so it was a major shift in power, and it forced Bill Clinton to become quite conservative in passing much of what Newt Gingrich wanted (you could say that it also helped him win re-election in '96 because he now had a villain to run against).